Code P402

[camlex]

Not long ago, I posted for Hesitation(Pulsing) and EGR cleaning.

Today I got CEL at 358,220 miles. Codes are P402 and P1410.

What should I do? Buy new or clean it.

How to clean?

Thanks in advance.

[George_Jetson]

97_egrvalve.pdf

I would take a look at P1410 first,I have attached a pdf with some info on this. Considering the age of the car, I would probably start with backprobing the position sensor, and measuring the voltage at the position sensor. You do not need to have the engine running, just turn the key to the ON position. If you have a small hand held vac pump (ie like one used for brake bleeding). You can slowly apply vac to the egr valve, while monitoring the voltage between pin 2 and 3 of the egr sensor. You should see the voltage sweep from 0 to 5 volts (do not worry about the polarity, because you are not really concerned about that for this test).

The position sensor is a potentiometer, (similar to the throttle position sensor). Over time the wiper will wear thru the resistor (between pin 1 and 3). When this happens, when you do the above mentioned test, you will see the voltage increase, then momentarily drop to zero, then continue to increase. In extreame cases (where the resistor opens) you will see the voltage stay at zero as you increase the vac, then when the wiper moves past the open spot, the voltage will abruptly jump to 5 volts.

Run this test, if there is any problems with the voltage signal, you will need to buy a replacement egr valve, as the postion sensor is a non repairable part.

[camlex]

Thank you very much.

If sensor check comes out okay, then can I clean EGR valve?

Thanks,

[George_Jetson]

97_egrvalve.pdf

Here's the complete writeup on that code. I read a good part of this, and from reading between the lines I assue that beyond the scope of this code it could get a little more complicated. But considering the mileage / age of the car, I would bet that it is the valve itself.

I would not recomend cleaning the valve for this code. The computer see the voltage feedback as out of range, so in this particular case, cleaning would probably not help. I would recomend purchasing a hand held vac pump (places such as harbor freight sell one for $20). It is good for checking sensors, vac diaphrams, and such. I have one, and so far over the years I have yet to use it for bleeding brakes, but just about everything else.

[camlex]

Thank you George,

I opened EGR today, Cleaned it was not that bad carbon build up. Opened Temp sensor, which was dirty,

After installed, I got CEL back, Run code again, got P402 only.

It's time for new. its serve for 358K not bad at all.

Toyota asking for $204 with 1 year warrenty. Orailly asking for $174 with lifetime.

Which one to buy?

After cleaning why P402?

Thanks,

[George_Jetson]

97egr.pdf

Interesting, I uploadeda file that also includes the 402 code. I admit I am a little confused that the P1410 code did not re-appear. Does your scanner display senor input values? If not use a DVM and closely check the egr valve position sensor, I would also recomend the hand held pump. I am starting to suspect that the egr valve is OK, and that your problem is the control soleniod is leaking by.

I would recomend purchasing the Harbor Freight ITEM 92474-0VG, for $20. It has a vac gauge built in. You could use it to manually open the valve, (key on, engine off). Back probe the egr connector with a couple Pins. Then you could use the pump to check the solenoid for leakage.

[George_Jetson]

97egr.pdf

Interesting, I uploaded a file that also includes the 402 code. I admit I am a little confused that the P1410 code did not re-appear. Does your scanner display senor input values? If not use a DVM and closely check the egr valve position sensor, I would also recomend the hand held pump. I am starting to suspect that the egr valve is OK, and that your problem is the control soleniod is leaking by.

I would recomend purchasing the Harbor Freight ITEM 92474-0VG, for $20. It has a vac gauge built in. You could use it to manually open the valve, (key on, engine off). Back probe the egr connector with a couple Pins. Then you could use the pump to check the solenoid for leakage.

[camlex]

I cleared code again, now showing P1411 and P402, you are right on changing Positioner sensor.

I bought from Orailly cost was $35. lets see what happen.

while i was cleaning last evening i noticed postion sensor was not pushing smoothly.

Thank you for all inputs.

[RX300ES300]

Since you have the sensor off already, measure the resistance, a good one should be >100K ohms at room temperature.

302 degree F, 2-4K ohms

212 degree F, 11-15K ohms

112 degree F, 69-89K ohms

[George_Jetson]

I cleared code again, now showing P1411 and P402, you are right on changing Positioner sensor.

I bought from Orailly cost was $35. lets see what happen.

while i was cleaning last evening i noticed postion sensor was not pushing smoothly.

Thank you for all inputs.

Sounds like you found it, if the position sensor was not moving smoothly that would explain the code. Glad to have helped. Have both codes cleared without returning? And have you noticed any difference with drivability ? (my quess would be not).

[camlex]

So far no CEL. Next visit to Austin, may be Lunch together.

drivability is improved, specially no hesitation and pulsetion.

Thanks

[George_Jetson]

Glad to hear it worked, I was starting to get real confused. It really sounded like the position pot. Yea next time you drop by maybe lunch, or at least a starbucks (I work odd hours).